Discovery of fibrotic intervertebral disc in mice

Abstract Mechanical overload on the spine is a critical factor in the onset of intervertebral disc (IVD) degeneration. However, the lack of a precise and reliable animal model impedes a comprehensive understanding of the pathogenesis associated with IVD degeneration. In this study, we identified the high prevalence of spontaneous fibrotic alterations in IVDs predominantly located in the tail base, spanning from Co3/4 to Co5/6 levels, as early as 28 days in mice. These fibrotic IVDs manifested characteristics including extracellular matrix fibrosis and a decline in cell density. We leveraged a finite element model of computational biomechanics to generate fully predictive, three-dimensional simulations of flexion motion in the mouse tail. Our simulations revealed that the caudal discs in the mouse tail base underwent various mechanical overloads. Hence, we propose that the caudal IVDs in mice can serve as a novel mechanical model for investigating the mechanisms underlying the pathogenesis of IVD degeneration.